The invention relates to wiper blades.
Wiper blades are known from DE 299 03 123 U1 which have a resilient insert with a tube-like elastomer sheath, into which a wiper rubber is inserted. With wiper blades of this type the supporting element is supposed to ensure the most even distribution possible of the contact pressure on the windshield emanating from the wiper arm over the entire area swept by the wiper blade. The supporting element is advantageously pre-curved in a suitable way to achieve the necessary even contact pressure of the wiper blade against the windshield. A supporting element of this type replaces the costly bow design with two splines located in the wiper body, such as is the practice with traditional wiper blades and is known, for example, from DE 15 053 97 A1.
The generic, known wiper blades do, however, have the disadvantage that their construction is costly. In addition to the supporting element, a wiper blade of this type furnishes transverse bars disposed perpendicularly to the supporting element, recesses located in the supporting element and locating grooves in the wiper rubber to receive the casing which surrounds the supporting element at least in sections. Such a construction results in an overall height which cannot be ignored and is accompanied by great disadvantages during operation. For example, the side of the wiper blade facing the air stream offers a fairly large target for the air stream striking the wiper blade. Furthermore, a substantial vacuum builds up on the back side of the wiper blade facing away from the air stream. It is true that the wiper blade constantly changes its position with respect to the oncoming air stream, generally carrying out a oscillating motion during operation, but even then one longitudinal side of the wiper blade is always facing the air stream more or less directly. Because of the air stream affecting the wiper blade, the wiper blade's contact pressure is reduced to such an extent that the wiper blade tends to lift off and flutter, rendering proper wiper performance impossible. Increasing the wiper blade's contact pressure against the glass can mitigate this problem at high speeds, but at low speeds, when the attempt of the wiper blade to lift is reduced, friction between the wiper blade and the glass is increased, resulting in undesirable noise and unacceptably high loading of the drive components and of the wiper rubber.
Wiper blades are known from DE 197 36 368 A1 of a type which essentially consist of a wiper body and at least one spline connected to this wiper body. These wiper blades, often described as “flat wiper blades”, have the disadvantage that the protruding splines generate extremely irritating noises, caused particularly by the air stream, and also represent a hazardous source of injuries.